First past the post is one of the oldest and simplest electoral systems. The logic is simple: the candidate with the most votes wins. It is the system in place in some of the oldest democracies, most especially the United States and the United Kingdom, as well as the largest democracy, India. This is also a system that is hotly debated, and proposals for reform are often advanced. This book addresses the following questions: What fosters or hinders reform of first past the post? When and why does reform emerge on the political agenda? Who proposes and who opposes reform? When and why do reform proposals succeed or fail? What kind of proposal tends to be put on the table? Are some types of proposal more likely to succeed? Why?The first chapter undertakes a comparative analysis of the conditions under which reform is initiated. The following chapters investigate in detail the politics of electoral reform in the United Kingdom, the United States, Canada, and New Zealand, the debates that take place, the proposals that are advanced, and the strategies deployed by the actors. These analyses contribute to a rich and nuanced understanding of why first past the post is often challenged and sometimes replaced.